In recent years, wearable devices that are worn on bodies of users have been developed. For example, wristwatch-type wireless communication terminals named as “smart watches” are developed. Usually, the wrist-watch type wireless communication terminals include a radio telephone function, and an antenna which performs transmission and reception of radio signals. A length of the antenna is decided by a wavelength of the signal which is transmitted and received by the antenna. For example, an appropriate length for the antenna which transmits and receives 800 MHz band signals in a cellular communication system is defined by the wavelength of the 800 MHz signal.
On the other hand, it is necessary to keep the wearable device such as the wristwatch smaller than conventional mobile phones. As recognized by the inventor, a limitation with small wearable electronic device is the limited space that is used to include components, (e.g., antennas), and therefore, the wearable device is preferred to include a least number of parts.